The Sacroiliac Joint: Problems with Back Pain During Pregnancy

Back pain is a very common complaint in the latter months of pregnancy for some women. Often the pain is described as a grabbing or stabbing sensation in the lower back near the buttock and base of the spine. Occasionally, the pain can manifest itself down one leg as well. The pain can be so severe that it affects all functions of a normal day-to-day life. Often times this pain is misdiagnosed as sciatica, which is due to impingement of the sciatic nerve, and is highly uncommon in a young healthy pregnant woman with no known prior back pain history. More than likely the cause of this debilitating low back pain is due to sacroiliac joint dysfunction. Pregnancy, in itself, actually amplifies this condition due to the specific hormones that are released in the body which have a direct effect on the ligaments in preparation for childbirth.

Anatomy of the SI Joint
The sacroiliac joint, commonly referred to the SI joint in the clinical setting, is one of two joints on either side of the pelvis where the sacrum, or base of the spine, joins with the large bone of the pelvis known as the ileum. The SI joint is very important as a "shock absorber" during weight bearing activities such as walking, standing up from a chair, and going up and down stairs. Typically the SI joint does not move very much, only about a couple of millimeters during certain activities. It's movement is a very complex combination of sliding, tilting, and rotating. The stability of the joint comes from being held together by several strong ligaments, which limit the motion of the joint yet stretch just enough to provide the necessary amount of play, or movement, in the joint. As a result of the complexity of movement of the SI joint and difficulty in objectively evaluating the movement, the diagnosis and treatment of SI joint problems can be sometimes overlooked as a causative factor in lower back pain in pregnant women.